@font-face {
    font-family: 'icomoon';
    src: url('../fonts/icomoon.eot?tomleg');
    src: url('../fonts/icomoon.eot?tomleg#iefix') format('embedded-opentype'),
    url('../fonts/icomoon.ttf?tomleg') format('truetype'),
    url('../fonts/icomoon.woff?tomleg') format('woff'),
    url('../fonts/icomoon.svg?tomleg#icomoon') format('svg');
    font-weight: normal;
    font-style: normal;
    font-display: block;
}
* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}

.tabboxes {
    /* 整个盒子 */
    width: 800px;
    height: 500px;
    margin: 100px auto;
    border: 1px solid pink;
}

.firstnav {
    /* 导航栏 */
    position: relative;
    width: 800px;
    height: 50px;
    /* border-bottom: 1px solid #ccc; */
}

.firstnav ul li {
    position: relative;
    width: 80px;
    height: 50px;
    list-style: none;
    text-align: center;
    line-height: 50px;
    border-right: 1px solid #ccc;
    border-bottom: 1px solid #ccc;
    float: left;
    overflow: hidden;
}

.bordernone {
    /* 切换按钮时 哪个li被选中底部边框变成none */
    border-bottom: none !important;
}

.del {
    /* 删除 */
    position: absolute;
    top: -20px;
    right: -20px;
    display: block;
    width: 40px;
    height: 40px;
    background-color: black;
    border-radius: 50%;
}



.del::after {
    /* 利用伪元素选择器添加×号到删除选项中 
    注意：一定不要忘记目录里放fonts文件夹 content 和 font-family也不要忘记写  */
    position: absolute;
    bottom: -12px;
    left: 7px;
    content: '\e919';
    font-family: 'icomoon';
    font-size: 8px;
    color: white;
}

.tabadd {
    /* 添加 */
    position: absolute;
    top: 10px;
    right: 10px;
    width: 30px;
    height: 30px;
    line-height: 30px;
    border: 1px solid #ccc;
    text-align: center;
    font-size: 16px;
}

.tabscontent {
    /* 内容面板 */
    position: relative;
}

.tabscontent section {
    position: absolute;
    top: 0;
    left: 0;
    display: none;
    width: 100%;
    height: 450px;
    margin: 50px;
}

.visible {
    /* 设置为显示 当切换到相应的li时添加这个类 */
    display: block !important;
}
